The present invention is directed to apparatus and methods for forming a multi-tier stack of like bags of granular material, such as cement, upon a pallet. As compared to the stacking or palletizing of relatively rigid articles, such as concrete block or cartons of canned goods, the machine palletizing of bagged goods presents additional problems in that the individual bags are not rigid and friction between the bag and machine surfaces which move relative to the bag can cause bags to bunch and the bag shape to become distorted and rip to spill the material in the bag. Ripping of the bag during handling with available machinery is quite common where, as in the case of cement, the bag is formed of paper. Care must be taken to handle the bag rather gently in that high impact forces can rupture the bag.
The present invention is directed to a bag palletizing machine in which frictional forces between the bag and machine surfaces which must move relative to the bag, and impact forces, are minimized.